Study of Relative Effectiveness of Climatic Factors on Reference Crop Potential Evapotranspiration in the Southern Fringe of Caspian Sea

Document Type : Research Paper

Authors

1 Water Eng. Dept., University of Tabriz

2 Dept. of Climatology, University of Tabriz

3 ِDept. of Climatology, University of Tabriz

Abstract

In this study the values of potential reference crop evapotranspiration were calculated using the FAO-56 Penman Monteith method in six stations located in southern shores of Caspian Sea. Trends in annual ET0 values of the stations were analyzed using the Mann-Kendall test. Then to determine the relative importance of climatic variables on ET0 in a certain station factor analysis conducted. To do this, correlation matrix (R) of seven variables also called similarity matrix was constructed. The significance of correlation coefficients were tested. Results of trends in ET0 showed that in all the stations (except Noshahr) trends of annual ET0 were upward and significant. The slopes of trend lines were positive in all the stations. Factor analysis showed that the first two factors accounted the total variance in the range of 56.5 per cent in the Rasht to 79.6 per cent in the Sari. The largest loading of the first factor is attributed to sunshine hours in the station Rasht, however, it was maximum air temperature in all other sites. In the case of the second factor, the largest loading belonged to wind speed (in Rasht, Gorgan, Sari and Noshahr) and precipitation (in Ramsar and Astara). The findings of this study can be helpful in optimum management of regional water resources.

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Full Text

در این مطالعه، مقادیر تبخیر- تعرّق پتانسیل گیاه مرجع (ET0) با روش پنمن-مانتیث برای شش ایستگاه‌ در حاشیه جنوبی دریای خزر محاسبه شد. روند تغییرات ET0  سالانه ایستگاه­ها با آزمون من کندال تحلیل شد. آنگاه تجزیه به عامل­ها برای تعیین اثر نسبی متغیرهای اقلیمی روی ET0 هر ایستگاه انجام شد. برای این کار ماتریس همبستگی (R) بین هفت متغیر اقلیمی به­عنوان ماتریس مشابهت تشکیل شد. معنی داری ضرایب همبستگی آزمایش شد. نتایج روند تغییرات ET0 نشان داد که در همه ایستگاه­ها (بجز نوشهر) روند ET0  سالانه مثبت و معنی­دار بود.  شیب خط روند  ET0ایستگاه­ها در همه آن­ها  صعودی بود. تجزیه به عامل­ها نشان داد که مجموع واریانس توجیه شده توسط دو عامل اول از حداقل 5/56 درصد در رشت تا حداکثر 6/79 درصد در ساری تغییر می­کند. بیشترین ضریب عامل اول در رشت ساعات آفتابی و در ایستگاه­های دیگر حداکثر درجه حرارت بود. بیشترین ضریب عامل دوم، متعلق به سرعت باد (در ایستگاه­های رشت، ساری، گرگان و نوشهر) و بارش (در ایستگاه­های رامسر و آستارا) بودند. نتایج این مطالعه در مدیریت منابع آب منطقه می­تواند مفید واقع شود

References

 
Esmailpour Marzieh and Dinpajouh Yaghoub (2012). Long-term trend analysis of potential evapotranspiration in the southern Aras River basin, Geography and Environmental Planning, Article 12, Volume 23, Number 3: 210-193. [In persian]
Babamiri Omid and Dinpajouh Yaghoub. (2014). Comparison and calibration of nine methods for estimating reference plant evapotranspiration based on mass transfer in the Urmia Lake watershed. Soil and Water Conservation Research (Gorgan), 21(5): 135-153. [In persian]
Babamiri Omid and Dinpajouh Yaghoub. (2016). Comparison and evaluation of twenty methods for estimating reference plant evapotranspiration based on three general categories of air temperature, solar radiation and mass transfer in the Urmia Lake watershed, Journal of Water and Soil Sciences (Agricultural Sciences and Technologies and Natural Resources), Year 20, 77: 145-161. [In persian]
 Hejabi Somayeh, Rezaian Hassan and Vazvaikhah Mohammad Amin (1401) Investigation of meteorological variables affecting the reference evapotranspiration process in the Urmia Lake basin. Iranian Irrigation and Water Engineering 48: 310-333. [In persian]
 Dinpajouh Yaghoub (1390), Analysis of the temporal changes in reference plant evapotranspiration (ET0) at Hamedan Station (Nojeh), Geographical Spatial Quarterly of Islamic Azad University Ahar, Year 11, No. 34: 260-286. [In persian]
Dinpajouh Yaqoub, Jahanbakhsh-Asl Saeed, Mousavi Jahani Leila (2011). Modeling potential evapotranspiration using meteorological parameters (case study: Lake Urmia basin). Journal of Geography and Planning 25(75): 127-139. [In persian]
Rezapour, Um-al-Bani, Amiri, Meysam, Ebrahimi, Mahboobeh and Amini-Ragan, Amin (2019). Study of drought in the southern half of Golestan province using factor analysis and GIS. Iranian Irrigation and Water Engineering 35: 125-142. [In persian]
Rezaei Banafsheh, Majid, Jahanbakhsh-Asl Saeed, Masoudian, Seyed Abolfazl and Jafari Shandi, Fatemeh (2018). Zoning of potential evapotranspiration in East Azerbaijan province using remote sensing data from MODIS product, Natural Geography 11(41): 38-48. [In persian]
Sabziparvar, Ali Akbar, Tafazzoli, Farzin, Zare Abyaneh, Hamid, Mousavi Bayegi, Mohammad, Ghafouri, Mohammad, Mohseni Movahed, Seyyed Asadollah and Marianji Zohreh (2008), Comparison of several models for estimating evapotranspiration of reference plants in a cold semi-arid climate, for the purpose of optimal use of radiation models, Journal of Water and Soil, Volume 22, Issue 2, Serial No. 65: 328-340. [In persian]
Shirzad, Monir, Feizi, Hajar and Rezaei, Banafsheh Majid (2012) Simulation of daily evapotranspiration of reference plants using artificial intelligence and its comparison with empirical methods (Case study: East Azerbaijan). Scientific Journal of Geography and Planning 26(80): 171-183. [In persian]
Asgari,Shams-ollah, Safari, Amir and Fathi Hojjatollah (2018) Investigation of flood potential in Jafarabad watershed. Journal of Applied Research in Geographical Sciences, Year 18, 50: 90-77. [In persian]
Vaziri, Zhaleh, Salamat, Alireza, Entesari, Mohammad Reza, Meschi, Mahmoud, Heydari, Nader and Dehghani, Sanich, Hossein (2008), Evapotranspiration of plants (Guidelines for calculating water requirements of plants). Translation and compilation: Working Group on Sustainable Use of Water Resources for Agricultural Production, National Committee Irrigation and Drainage of Iran, first edition, Tehran: National Committee of Irrigation and Drainage of Iran, 355 pages.[In persian]

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